Field of the Invention
This invention relates in general to distillation units commonly referred to as evaporators employed for several purposes such as converting sea water into fresh water for drinking, recovering metals and chemicals for re-use as in plating operations, removal of toxic or radioactive material or simply to convert by evaporation and condensation, under vacuum, non-potable water into pure drinking water for use in the home, recreation vehicles, small boats, etc.
Previously, sea water distillation units, with the exception of U.S. Pat. No. 3,219,555 issued to Poindexter, et al., have employed expensive copper nickel or monel construction using tightly bent small diameter "U" tube bundles for heat exchangers. Except for Applicant's U.S. Pat. No. 3,302,373, all were dependent on sea water powered eductors to pull vacuum. The high velocity sea water corroded the nozzles and caused back firing into the product water. Applicant's U.S. Pat. No. 4,548,257 (which is incorporated herein as if fully set out herein) disclosed many applications for bayonet tube heat exchanger designs; new applications are disclosed herein. U.S. Pat. No. 3,015,355 issued to Humphrey discloses a twisted enhanced tube applicable to the bayonet tube configuration delineated in one of the embodiments of the present invention.